METREL MI 3399, Инструкция с упражнениями

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Power and Voltage Quality Trainer AD 2
– MI 3399
198
4.11 Exercise 11
– Phase (switch) failure
This practical example will reproduce an event where two phases are interchanged
during switching power feeding form one transformer to another. During such an event
excessive current inrush can occur, which could cause feeder tripping.
L1
L2
L3
L1
L2
L3
L1 L2 L3
Transformer 2
Fe
ed
in
g
Phase L2 and L3 are
interchanged during switch
occurance
Figure 4-90: Phase switch
In order to simulate such an event, please set the switch S10 in the Application Trainer
to ON as shown in the table below. The remaining switches should be set to OFF. The
Application Trainer will switch between phases L2 and L3 every 10 seconds.
Switch Description State
S10 Phase (switch) failure
ON
In practice we usually don’t know where the problem is; therefore we recommend to
start observing voltage, current and THD. This can be done by entering the U,I,f MENU
in the MEASUREMENT MENU, as shown below.
Figure 4-91: Real time measurements of voltage and current